For some people it's a matter of more exposure and getting something they made out there. I enjoy the little payment I've received for things I've developed(Feed) but the money isn't as good as seeing people playing a game that I made and enjoying it. As cheesy as it is, I enjoy bringing that happiness/entertainment to other people.

On second thought, i'm not so sure adding steam integration to your game is such an impossible feat

Now that you can make a stand-alone executeable (.exe) for the game, all it would take now is to be able to wrap that .exe in the steamworks C++ SDK. If you are able to launch the exe in your program you will be able to get it running in Steamworks, adding steam achievements integration is a little more tricky. I might look into doing this actually.

Some minor C++ knowledge is necessary but the Steamworks SDK and information on how to use and to get your game working with it is available here:https://partner.steamgames.com/

If you can manage to get that working, getting your byond game listed on steam greenlight won't be too difficult.